[Paraview] documentation of time support

[Thompson, David C]

You should set the vtkStreamingDemandDrivenPipeline::TIME_STEPS()
information key on the output vtkInformationVector to a list of the time
steps your filter can output (or set
vtkStreamingDemandDrivenPipeline::TIME_RANGE() to the min/max
values if your filter behaves continuously over time).

Assuming that you are not populating a vtkTemporalDataSet yourself,
your RequestData() member should examine the
vtkStreamingDemandDrivenPipeline::UPDATE_TIME_STEPS() value
of the output vtkInformationVector object and fill the output dataset
with the first time step listed. Then it must set the
vtkDataObject::DATA_TIME_STEPS() key on the output vtkInformationVector
to the first time step from UPDATE_TIME_STEPS(). Because you
are not populating a vtkTemporalDataSet directly, the pipeline will
call your RequestData() member with a different value in
UPDATE_TIME_STEPS() each time. The pipeline executive stores
all these datasets as blocks in one big vtkTemporalDataSet that
gets passed to the next filter downstream.

If your filter does populate vtkTemporalDataSet objects directly,
you are responsible for adding one block to the output for each
value in the UPDATE_TIME_STEPS() vector and setting DATA_TIME_STEPS()
to contain the same values as UPDATE_TIME_STEPS().

For ParaView, you should also have this in your reader/filter's XML:
     <DoubleVectorProperty
         name="TimestepValues"
         repeatable="1"
         information_only="1">
       <TimeStepsInformationHelper/>
if your filter has discrete time steps or:
     <DoubleVectorProperty name="TimeRange" information_only="1">
       <TimeRangeInformationHelper/>
     </DoubleVectorProperty>
if your filter output varies continuously with time.

Are you using all the keys above and still not getting the correct
behavior from ParaView?

    David

________________________________________
From: paraview-bounces at paraview.org [paraview-bounces at paraview.org] On Behalf Of Dominik Szczerba [dominik at itis.ethz.ch]
Sent: Tuesday, August 05, 2008 00:47
To: paraview at paraview.org
Subject: [Paraview] documentation of time support

I am trying to find documentation of time support in VTK/Paraview. I
found a Wiki page about time support, but that is very general. I have
specific questions e.g. how do I inform PV about time extents, timesteps
etc. I assume this should be done in RequestInformation, but setting it
there does not make PV aware of it. Should it be set somewhere else too?

Any pointers are appreciated.
Thanks,
Dominik

--
Dominik Szczerba, Ph.D.
Foundation for Research
on Information Technologies in Society
http://www.itis.ethz.ch
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